Yes apartment prices can be considered reasonable but actual houses are approaching the same levels as Vancouver.
Also those $250k apartments usually have $500/month maintenance fees attached. Not all, but some.
This is only true for federal taxes. States aren't required to follow federal tax treaties. So California, for example, doesn't recognize any tax treaty with Canada. There are lots of ways you can wind up getting taxed twice.
I know many people who have been in this position.
For states without state income tax, of course, that changes things.
At my present income, if Canada wanted a slice of the pie I'd owe a very small cheque to them each year. The paperwork would be more painful than the tax.
And that's assuming you maintain Canadian residency - if not then you're only on the hook for federal income tax, which is strictly going to be lower than whatever you're paying California (you only pay the difference to Canada due to tax treaty), so your total Canadian tax bill will be a whopping $0.
I realize that this is a hypothetical, but FYI the CRA has rules that kick in when you're paying taxes and not a resident (e.g. you're a "deemed resident", "factual resident", etc.). Generally you will still be taxed in the province where you have significant ties or last resided.